Illinois announced its first probable case of monkeypox on Thursday — one of a small, but growing number of cases across the country.

The case is in a male Chicagoan who recently traveled to Europe, according to the Chicago and Illinois departments of public health. The person did not require hospitalization and is in good condition, isolating at home.

The case remains isolated, and “at this time there is no indication there is a great risk of extensive local spread of the virus, as monkeypox does not spread as easily as the COVID-19 virus,” according to a news release from the health departments.

The city and state health departments are working with the Centers for Disease Control and Prevention to identify people who may have been in contact with the infected person. Initial testing was conducted at an Illinois Department of Public Health laboratory, and the CDC is now conducting testing to confirm the result.

In all, 19 confirmed cases have been reported nationwide, according to the CDC.

This 2003 electron microscope image made available by the Centers for Disease Control and Prevention shows mature, oval-shaped monkeypox virions, left, and spherical immature virions, right, obtained from a sample of human skin associated with the 2003 prairie dog outbreak. 

Monkeypox is a rare viral illness that typically begins with flu-like symptoms and swelling of the lymph nodes before progressing to a rash on the face and body. The illness typically lasts two to four weeks.

It can be spread from person-to-person through close physical contact with monkeypox sores; items that have been contaminated with fluids or sores, such as clothing or bedding; or through respiratory droplets during prolonged face-to-face contact, according to the state and city health departments.

Anyone can get monkeypox, but, so far, many of the cases have been among gay, bisexual, and other men who have sex with men, according to the CDC.

Monkeypox is endemic to parts of central and west Africa but has been spreading beyond that region in recent weeks, to countries that don’t usually have cases. In Africa, people can be exposed through bites or scratches from rodents and small mammals, preparing wild game, or coming into contact with an infected animal or animal products.

Confirmed U.S. cases have been reported in California, Colorado, Florida, Georgia, Massachusetts, New York, Pennsylvania, Utah, Virginia and Washington.

People with new, unexplained rashes, sores or symptoms should see a health care provider to see if they have the virus, and they should avoid being intimate with anyone until the provider sees them, according to the state and local health departments.